SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c23203fc6186ee5db35d2917c4bf5be4a64e59c9f664b6b67ed223b3aa296fc1' 
  AND token = 'mKQ1O1RQgZB5UjNQpwKwmAAnhfVBwBG4k76pfQ/YBLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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