SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3c2f8c9f6003e94d19152b150ac7d97c77735ad348e0e5383c1040859b59122' 
  AND token = 'EQz1tcI6UgwJ/wzO7g3DvbzjHqsig9hkrkRfPC2VH/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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