SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd31875e68a22a77884868e771c1ce392a60126ae7eec89b4376d615d8dba96d1' 
  AND token = 'jIPAM1bPAXmp0axDEq3JTpIF5E/MPyar69UNvm9X1/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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