SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b7ccee50906dc5b141057e3aaf8c5ba68d3eed8a8c375a70fe36cd849520d939' 
  AND token = 'FqqYEI0T9s0DEF3OtuuArOmvNxjcbhrcQ2x3FIePZw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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