SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c8466b9ac33d2a4d5a4eaa0c8fde0990f807d60bbe8ff92ad362e301a815036' 
  AND token = 'zUWwO1q0Y1yq4zW1MP3Qehez3ZFgf6H2YtCVFUORjEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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