SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49192e02428f9f246d7a5ef874ba927c4ae164fb8e700d969b277ae27a15949b' 
  AND token = 'QtVeAlw72ScFNMgn/j9NscAKsRIKExawpSLoP/NKmr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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