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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bb61f6a1c3aff6278080ab812813362785177dc5c233bbc83f357e90b9f1dc7d' 
  AND token = 'NF+aZSMwDTZJoCzZNEQZ6ZnaLU/Zj8cTdR4gn1+L1RA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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