SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6929a2f034c24edd323e7eb494aead7a17f8ad2f41e85b0821b7213a6dad9ba7' 
  AND token = 'LhqJAghur3mYUrN0575j3fTZFya8V0N/9hZMLNv5qm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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