SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3820d95efc1025b86493511fd3e566b475dfb9ee750a5db1ef6c069dd088bb76' 
  AND token = '8uJ3npTWpcN8HvmqPh0IUrZ36BGOpqGDb7jcI2iPBTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}