SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5b272373d298eca936030f3797a21a06c1792faad4e6a63286feba93e157cbdb' 
  AND token = 'Bif0FD/ixGRLy1t8mjZu38AMu0gbIaYQtrujgAcilBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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