SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6c13e747fdf712256d4c88b6affbb1c11796a3e035c1300a67491ed54dea9c9' 
  AND token = 'Cg3n6bho593TIhfBAkAN3PaWYTSOHhC9QMr/Byqpbds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}