SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb3a210841d6147184daf8153fb03b3eab50048b96bf645282f33f78b323b56e' 
  AND token = 'U0fT8KbuOJZ2gBCppuTDWyB/sW7qXBioyzZpikZ64Rc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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