SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0cdf2a5af9acf7d4e4d0165835cf55598ba844b9d307f49d6b3f43bec5d94e1' 
  AND token = 'nSVzq2QjmdwlBNEqP7ynQTsjtd9rTIwFh0ZHW9/KHq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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