SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cc75d1c619b68d1a12263c9df58a683477b0b116f88879e0fbe2050d2d1b88d' 
  AND token = 'oWf/7AoTPr4SxvD5smCv9RGBzlpg53awi+svJs46jMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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