SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7f510b8b475bbb0134dab2c8aa0240ec99ca662adfcf38aafdbfbe35d31fec4' 
  AND token = 'thpBmdq2s5adXgU7PKd3dNDY38rFxa3YErwUPMJ9TUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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