SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57f66c2d94fc4537cf081ec468e6ffe2376f80ce697f87155688d736fa922fc9' 
  AND token = 'aBEUknZHlPXco4TXzqYLs+a6oO+OxWNMJVNOMqqBF48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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