SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5b0a09dcdccb0ed096d8b682f7131d8436d22374b055b2fdb3ecdcbf55fcae1' 
  AND token = 'oerdE2KobEKfTaFFKv9B8LY3mcdDvWeRMK96KqM3IDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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