SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbd27576fec659a542f389fa259f86ccf483ff1aac79fa5b4d793ff1934eafb9' 
  AND token = 'vgbsdDH73y5PXcAVurjsHXSbNulW1beujhZCkRecYL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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