SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7a772d7f0b8358fba0fcf0a2509c8d4b2e6f1cdcad3ceacfc34491b8ed4b5f5' 
  AND token = '52LSi//JPBJhN57C3D0ShSMv95w8D2dOK/sICPhCRlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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