SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffe3c15ed9a85788282a57177f050ea2aa9b3df4f32984808d4eb88922e4f651' 
  AND token = '/mF+hCF8BxRomvfPmgoQOW1cE+Bghp1xRy+KDZUaJSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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