SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'dcc3f677a1de08330490f6f382c75e2cbc2821cc149bf94a8abf0486b092c6a2' 
  AND token = 'MHoHbCtBb8q7rvukxnijhzKPMMpUJTDeqxKL0jyw0gI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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