SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a520153d9e1b2a1c5715913ae5108b8fe7d51fc93f6de59ec14e57c7bfc5ef0e' 
  AND token = 'OFb03bfcktVhnBVq3ypHYaA48TZnX93PgBaIg98XhbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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